 /*******************************************************************************
  * Copyright (c) 2000, 2004 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Common Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/cpl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.ui.internal.dialogs;

 import java.net.URL ;

 import org.eclipse.jface.dialogs.IDialogConstants;
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.jface.wizard.WizardPage;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.ui.PlatformUI;
 import org.eclipse.ui.internal.WorkbenchMessages;
 import org.eclipse.ui.internal.util.BundleUtility;


 /**
  * An abstract class with some utility methods and common values to share
  * between preference import/export wizard pages.
  *
  * @since 3.0
  */
 abstract class AbstractPreferenceImportExportPage extends WizardPage {
     
     /**
      * The title for all pages involved in the export operation.
      */
     protected static final String EXPORT_TITLE = WorkbenchMessages.getString("ImportExportPages.exportTitle"); //$NON-NLS-1$
 /**
      * The title for all pages involved in the export operation.
      */
     protected static final String IMPORT_TITLE = WorkbenchMessages.getString("ImportExportPages.importTitle"); //$NON-NLS-1$
 /**
      * The default extension for preferences files.
      */
     protected static final String PREFERENCE_EXT = ".epf"; //$NON-NLS-1$

     /**
      * Retrieves the image descriptor from the given relative path. The path is
      * relative from the "icons/full" directory.
      * @param relativePath The relative path; should not be <code>null</code>.
      * @return The image descriptor if it can be found; otherwise, the "missing
      * image" descriptor.
      */
     protected static ImageDescriptor getImageDescriptor(String relativePath) {
         String path = "icons/full/" + relativePath; //$NON-NLS-1$
 URL url = BundleUtility.find(PlatformUI.PLUGIN_ID, path);

         return url != null
                 ? ImageDescriptor.createFromURL(url)
                 : ImageDescriptor.getMissingImageDescriptor();
     }

     /**
      * Whether this page was opened in export or import mode. Since there is a
      * significant amount of overlap, the import and export pages are not
      * separate classes.
      */
     protected final boolean export;
     
     /**
      * Constructs a new instance of a preference import/export page with the
      * given name.
      * @param name The name of the page to be constructed; must not be
      * <code>null</code>.
      * @param exportWizard Whether this page should be opened in export mode.
      */
     protected AbstractPreferenceImportExportPage(final String name, final boolean exportWizard) {
         super(name);
         
         export = exportWizard;
     }
     
     /**
      * Computes the width hint for the given button. The width hint is the
      * maximum of the default width and the minimum width to display the button
      * text.
      * @param pushButton The push button for which to compute the width hint.
      * @return The width hint, which should be a positive integer capable of
      * displaying all the text in the button.
      */
     protected int computePushButtonWidthHint(Button pushButton) {
         final int defaultWidth = convertHorizontalDLUsToPixels(IDialogConstants.BUTTON_WIDTH);
         final int minimumWidth = pushButton.computeSize(SWT.DEFAULT, SWT.DEFAULT, true).x;
         return Math.max(defaultWidth, minimumWidth) + 5;
     }
 }

